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Regulators; these are devices that are used to change the pressure coming from the compressor receiver in all, or just part of, a compressed air system, depending on where they are installed.
A regulator will be installed in a specific orientation to the air line air flow - usually indicated by an arrow on the body of the regulator- as compressed air is normally meant to travel through them 'one way'.
The regulator will usually have an air gauge which visibly indicates the air pressure on the downstream side of the unit, and usually displaying the set point that was dialed in with the adjusting knob or nut.
For the sake of simplicity, we've not included a gauge in the drawing, nor have we shown the detail of the actual 'internals' of a regulator, which are far more complex than shown.
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The inner components of a regulator act very quickly, increasing or decreasing the flow so that the downstream pressure remains fairly constant. The accuracy of pressure downstream is directly related to the quality of the regulator.
Regulators in compressed air systems can only lower the pressure. Dialing the pressure up past the supply line pressure can not increase the downstream pressure past the supply pressure level, despite how many times you turn the knob!
Compressed air is a fluid. Pressure exerted at any one point in the closed system will be transmitted equally throughout the entire system.
Each time your compressor cycles on, whether “kicking in” due to low receiver pressure or the cycling of the pilot unloader valve on a continuous run compressor, it starts building pressure in the system receiver and lines again, and that sudden increase in pressure will generate a pressure-pulse in the compressed air throughout all your lines in the plant. This may be negative to the application.
Having a receiver will dampen the pulse somewhat, but not entirely.
If the set points on your compressor are 120 PSI on the high side, and 100 PSI on the low side, and you set your pressure regulator for 90 PSI going into your application, in theory that application should never see a pressure fluctuation, regardless of how many times the compressor kicks in or out. This has benefits in terms of regular cycling of actuators etc.
The exception to this will be if the demand for compressed air far outstrips the ability of the compressor to supply it. When this occurs, the available air pressure will continue to fall past the regulator setting, and the air supply in the lines to the application will, too, see the pressure start to fall. When demand stops, air pressure will start to build, and a pressure-pulse can occur in the lines until the pressure is up past the regulator set point.
Another benefit of a regulator, and why you'd want many throughout the system, is that by adjusting the pressure down to the lowest functioning level at each air-using application, you can save many dollars in compressed air generation cost.
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Regulators can be relieving or non-relieving, depending on your application.
If you were regulating the pressure of a noxious or expensive gas, you'd select a non-relieving unit to prevent off-gassing of that poisonous gas into the plant atmosphere through the regulator.
Most industrial systems use a relieving regulator, which means that if the downstream pressure exceeded the pressure setting on the regulator, then the higher downstream pressure would be allowed to vent or 'relieve' to the atmosphere back through the regulator.
General purpose regulators can be expected to maintain a pressure level within plus or minus 2-5 PSI range on average.
Precision regulators can usually hold a line pressure within plus or minus 1/2 - 1 1/2 PSI of the set point.
Larger pressure regulators can be air-piloted and slaved to smaller, remotely installed, regulators.
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Did you know that...
"Optimization of compressed air systems can provide energy efficiency improvements of 20 to 50 percent."
Source: http://www.eere.energy.gov
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